Deleterious mutation accumulation in organelle genomes

摘要: It is well established on theoretical grounds that the accumulation of mildly deleterious mutations in nonrecombining genomes a major extinction risk obligately asexual populations. Sexual populations can also incur mutational deterioration genomic regions experience little or no recombination, i.e., autosomal near centromeres, Y chromosomes, and organelle genomes. Our results suggest, for wide array genes (transfer RNAs, ribosomal proteins) diverse collection species (animals, plants, fungi), an almost universal increase fixation probabilities arising mitochondrial chloroplast relative to those recombining nuclear genome. This enhanced width selective sieve does not appear be consequence relaxed selection, but explained by decline efficiency selection from reduction effective population size induced uniparental inheritance. Because very low mutation rates (on order 10−4 per genome year), fitness resulting such long-term process, likely imperil many time scales less than million years, perhaps playing some role phylogenetic lineage sorting 10 100 years.